Non-contact power supply technology represented by electromagnetic induction is studied. The non-contact power supply technology is used in shavers, electric toothbrushes, and the like. In recent years, with presentation of magnetic field resonance technology being a trigger, non-contact power supply is eagerly studied more and more again.
Further, there is a known wireless power supply system which transmits power from a power transmission antenna to a power reception antenna by a wireless method, the wireless power supply system having a detecting unit detecting information related to a disposition state of the power reception antenna, a plurality of driving units driving a plurality of power transmission coils of the transmission antenna separately, and a control unit controlling an electric current flowing through the power transmission coils via the driving units based on at least the information related to the disposition state of the power reception antenna (see, for example, Patent Literature 1).
Further, there is known a non-contact power transmission device which has N (N is an integer of 2 or more) power transmission circuits and a control means controlling the N power transmission circuits, in which the transmission circuits have a transmission side LC tank circuit constituted of a capacitor and a power transmission coil which are connected in series and an oscillator circuit supplying power to this transmission side LC tank circuit, the power transmission coils of the N power transmission circuits are disposed in a matrix form, and the control means controls phases of signals generated by the respective oscillator circuits of the N power transmission circuits so that phases of changes in magnetic fields which arrive from at least two power transmission coils out of the power transmission coils of the N power transmission circuits are aligned in power reception coils of power reception circuits (see, for example, Patent Literature 2).
Patent Literature 1: Japanese Laid-open Patent Publication No. 2008-283789
Patent Literature 2: Japanese Laid-open Patent Publication No. 2011-199975
However, in Patent Literature 1, the description of specific means for obtaining information related to the disposition state of the power reception antenna is insufficient. Further, in Patent Literature 2, the description of specific method is insufficient for making the phases of changes in magnetic fields which arrive from at least two power transmission coils align in the power reception coils of the power reception circuits.